2. Only visible light is visible, but infrared and ultraviolet rays are invisible. Color is that photons hit the retina, transmitting energy to it, and the dorsal nerve perceives it, so it produces the feeling of light. Photons of different colors have different frequencies and energies, so people can distinguish them. Color and light color have no meaning, and frequency determines color. E=hv, then the photon energy calculation formula, V is the frequency, fixed by different light.
3。 Light is a quantum of energy. After irradiation, it will be transmitted to him, and his energy will increase. It also conforms to the law of conservation of mass.
As I said, light has wave-particle duality, its wave is probability wave, and the photons in it can go anywhere. A straight line of light in a homogeneous medium, such as a curve through an inhomogeneous atmosphere.
5. It can be converted. Have you ever heard of radio waves? First of all, it is a kind of light. It is produced by L-C oscillating circuit, that is, electricity. Secondly, there is a solenoid that can change electric energy into magnetic energy. In this sinking, optical electromagnetic waves are produced.
6. The sixth question is completely incomprehensible. Now that the light has been converted, how can it pass through the plane again?
7. It's simple. Electromagnetic waves are light and radio waves are light. Of course, they are used. The reaction of color originally indicates the energy of light, and seeing color means that light energy has been transmitted.
Okay, I've been answering for 20 minutes. I wonder if I can understand a little. Light is an abstract concept.